Multiple-fuse plug



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- ATTORNEY.

April 14, 1925.

w. H. TAYLOR ET AL MULTIPLE FUS E PLUG Filed mayffi 1922 v Patented Apr. 14, 1925.

UNITED STATES PA ENT OFFICE.

WILLIAM H. TAYLOR, CHARLES W. DOWNS, AND JACOB W. BARZBEY, OE MICHIGAN.

DETROIT,

MULTIPLE-FUSE 1 mm.

Application filed May 6, 1922. Serial No. 559,075.

To all wlz0' m it may concern:

Be it known that we, WILLIAM H. TAY- Lon, a subject of the King of Great Britain, and CHARLES W. Downs and JACOB W. BAR- BEY, citizens of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented a certain new and useful Improvement in Multiple-Fuse Plugs, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification. This "invention relates to multiple fuse connecting one of the elements at a time in the circuit, the said means including indicating means to indicate which fuse element is connected. With the fuse plugs now commonly in use containing a single fuse ele-' ment when the fuse element is blown it is necessary to discard the entire fuse plug as being unfit for further use and therefore one of the main objects of the invention is to provide a fuse plugv of the character described which may be blown a number of times before being discarded. Another object of the invention is to provide a fuse plug of the character described provided with means for separately indicating which fuse elements are blown and which are not blown. A novel feature of. the invention resides in the provision of means for indicating which fuse element is in the circuit in combination with means for indicating whether or not the said fuse element is blown, said indicating means also indicating the fuse elements which are not blown so that the user may easily change the contact from a blown fuse element to one which is not blown. A further objectof the invention is to provide a multiple fuse plugwhich is very simple and eflicient in operation and fuse plug.

Fig. 1 is an elevation of a multiple fuse plug embodying our invention.

Fig. 2 is a plan view gf the fuse plug.

Fig. 3 is ayertical section through the Fig. 4 is a bottom view of the fuse plug.

Fig. 5 is an elevation of the fuseplug with the casing removed.

Fig. 6 is a perspective viewof one of the fuse elemen Fig. 7 is a plan view of the cover for the body of the fuse plug before being folded.

The fuse plug comprises a main body 1 of porcelain or other insulating material and a series of notches or apertures 2 are formed in this body 1 which open at 3 through the upper enlarged part 4 of the body as shown inFig. 3. The enlarged portion 4 of the porcelain is provided with a series of gas vents 5 shown more particularly in Fig. 5, the upper face of the porcelain being flat to receive a mica disc 6 "which is cemented thereon. The lowerend of the plug is provided with a series of notches 7 as shown in which wlll blow when too great a load is placed on the circuit. The fuse elements are positioned with "the ends 9 thereof engaging the seat 8 of the notches 7 and extend upwardly through the notches 2 so that the highest portion thereof is the portion 11 which is the nearest-to the mica cover 6. After the fuse elements have been set .in place a paper ring 12 is slipped thereover having a series of radiating portions 13 which are bent upwardly to cover the notches 2 as shown in Figs. 5 and 7. This rin 12 may be of paper as stated or may be ma e from a sheet of asbestos paper the object being to prevent the burning through of the threaded brass shell or casing 14 when the fuse elements are blown. A fibre or asbestos ring 15 is positioned over the paper ring 12 and is cemented in place, the said ring 15 engaging the fuse elements 10 and holding the ends 9 thereof in place in the notches 7. The brass shell 14 is then slipped in place and is secured to the porcelain by indenting the casing 14 at two diametrically ends 18 of the fuse elements are bent over the upper edge of the shell 14 as shown in Fig. 3 and a drop of solder is applied to the end 18 of each fuse element as shown in Fig. 1 1

to secure the same to the casing and form a good contact. A cap 19 is then positioned over the upper end of the casing and covers the edge of the mica disc 6, the lower edge 20 of the cap being inturned beneath a shoulder 21 formed in the porcelain to hold it in place. The body 1 is provided with a central aperture 22 opening into a recess 23 in the upper end of the body and a brass rod 24 extends upwardly through the aperture 22 and is provided with a pointer 25 on the upper end thereof within the recess 23. A coiled spring 26 is interposed between the pointer 25 and the lower end 27 of the recess 23 about the rod 24 and holds thepointer and rod in the uppermost position. The rod 24 at the lower end is provided with a por tion 28 having an upwardly extending point 29 which extends into the notch 7 and contacts the end 9 of the fuse element therein due to the tension of the spring 26.

When the fuse plug is threaded into. a socket the brass shell 14 forms the outer contact member and theportion 28 of the rod 24 forms the central contact member. In the position shown in Fig. 3 the flow of current is through the member 28, point 29, through the fuse element on the right of Fig. 3 and-portion 11 thereof and thence to the casing 14. When the fuse element is blown the break occurs in the portion 11 thereof which, being near the mica disc 6 blackens the portion of the mica disc directly over the respective opening 3 and as the disc 6 is cemented to the porcelain only i the portion of the mica directly over the respective opening can be blackened, thegases escaping through the vent 5 and between the cap 19 and portion 4 of the porcelain. By concentrating the blowing of the fuse to a Very small portion of the mica disc the mica over the respective opening is colored a dense black so that no mistake can be made in distinguishing between a fuse that is blown and one that is not. Also by cementing the mica disc to the porcelain it is impossible for any of the mica to be blackened except in the portion directly over the blown fuse element. By pulling down on the portion 28 the rod 24 is drawn downwardly thus compressing the spring 26 and the point 29 is inserted in another notch 7 and when released the point 29 will be forced into contact with the portion 9 of the respective fuse element by the spring 26 thus connecting a new fuse element in the circuit. It is also to be noted that the point 25 is directly over the point 29 and always points to and indicates which fuse element is in the circuit. In other wordsthe fuse element contacted by the point 29 so that it is very simple to remove the plug from the socket {111d set the contacts to connect an unblown fuse element in .the circuit.

The fuse plug, as hereinbefore described, is efficient in operation for all the ordinary purposes but we have found it advisable to introduce what we have termed an arc breaker which is shown at the right side of Fig. 3 at 50. This consists of a strip of insulating material positioned in and extending from the inner end of the fuse chamber practically to the bottom of the bend of the fuse member 11 and adapted to be readily inserted in the chamber" after the fuse element is in position. It will be noted from Fig. 3 that, with the fuse blowing at the point of the bend, which is the point of least resistance, the are would tend to pass between the broken ends and, due to introduction of the member 50, the are necessarily travels around the end of the strip 50. This strip electricallyshields the legs of the bend one from the other so that the arc tends to immediately become lengthened about the end of the member 50 and blows out almost immediately and therefore produces minimum degree of heat and little internal pressure in the fuse chamber. Without the shield 50 the'arc continues to lengthen until a high degree of heat is developed in the fuse chamber resulting in a high internal pressure and puncture of the shield 14. l/Ve have shown only one are breaker 50 but it is to be understood that the plug may be used with all the fuse chambers provided with the are breakersor without depending upon the amperage of the current in the system in which the fuse plug is to be used.

It is further to be noted that the vents 5 vent to atmosphere between the flange of the cap and the body 4 of the porcelain member as the cap does not in practice fit so tightly on the member 4 asto prevent an egress of gases therebetween.

From the foregoing description it becomes evident that the device is very simple and efficient in operation, is of comparative ly low manufacturing cost and provides a fuse plug which may be used many times before being discarded and which accomplishes the objects described.

Having thus fully described our invention, what we claimis- 1. In a fuse plug, a body of insulating material having a central longitudinal aperture and a series of longitudinal apertures spaced radially thereabout, the lower end of the body being provided with a series of notches arranged radially between the central aperture and the series of apertures, a

transparent disc cemented on the upper face of the body and covering the apertures therein, a series of fuse elements each having an end extending into one of the notches of the body, the said fuse elements each extending upwardly into one of the series of apertures and. being provided with a portion of least current capacity adjacent the transparent disc, a metal shell secured to the body, the "opposite ends of the fuse elements being secured to the said shell, a foldablevpaper member closing the apertures of the body to the shell, a rod extending upwardly through the central aperture and having a pointer on the upper end thereof indicating the fuse element in the circuit,

the lower end of the rod being return bent and adapted to contact the ends of the fuse elements, in the notches of the body, and a spring holding the return bent end of the rod in contact with the respective fuse element. I v

2. In a fuse plug, a body of insulating material having a central longitudinal aperture and a serles of longitudinal apertures spaced radially thereabout, the lower end of.

the plug being provided witha series of notches in radial alignment with the series of longitudinal apertures, a transparent disc cemented on the upper face of the body and covering the apertures therein, a series of fuse elements each mounted in one of the series of spaced longitudinal apertures, the

said fuse elements being each provided with a portion of least current capacity extending adjacent the transparent disc, each fuse element being provided with an end extending into one of the notches of the body, a metal shell secured to the body, the opposite ends of the fuse elements being secured to the metal shell, a rod rotatably mounted in the central aperture of the body, a pointer on the upper end of the rod, the said rod being provided with a return bent end adapted to engage the ends of the fuse elements in the notches of the body, and yieldable means allowing positioning of the said return bent end in any of the series of notches, the said yieldable means holding the return bent end in contact with the respective fuse element when the rod is released.

3. In a fuse plug, a body of insulating material having a lower end of smaller diameter than the upper end, the said body being provided with-a central aperture and a series of apertures arranged thereabout opening through the sides of the lower end of the body, a series of fuse elements each I positioned in one of the series of apertures andhaving the lower ends thereof arranged radially about the central aperture of the body, a transparent disc secured to the upper face of the body and covering the apertures therein, the fuse elements extending upwardly into the apertures and each having a portion of least current capacity adjacent the transparent disc, a metal shell secured to the lower end of the body and closing the series of apertures opening therethrough, the opposite ends of the fuse elements being secured to the said shell, a. rod rotatably mounted in the central aperture provided with a return bent end adapted to engage the lower ends of the fuse elements, a point-- er on the upper end of the rod in alignment with the return bent end and a spring holding the return bent end of the rod in contact with the respective fuse element.

4. Ina fuse plug, a body of insulating material havinga lower end of smaller diameter than the upper end and having a series of apertures through the upper end of the body and through the sides of the lower end thereof, the said body being also provided with a central aperture, a series of fuse elements each positioned in one of the series of apertures of the body and having the lower ends thereof arranged radially about the central aperture, a transparent disc secured on the upper face of the body, the fuse elements being each provided with a portion of least current capacity adjacent Y the transparent disc, a metal shell secured to the lower end of the body, the opposite ends of the fuse elements being secured to the said shell, a rod rotatably mounted in the central aperture provided with a contact point adapted to engage the lower ends of the fuse elements, and a pointer on the upper end of the rod in alignment with the said contact point. I

5. In a fuse plug, a body of insulating material having a central longitudinal aperture and a series of longitudinal apertures spaced radially thereabout, the lower end of the body being provided with a notch for each of the series of apertures, a transparent disc secured on the upper face of the body and covering the apertures therein, a series of fuse elements each having an end extending into one of the notches of the body and each extending upwardly into one of the series of apertures and provided with a portion of least current carrying capacity adjacent the transparent disc, a metal shell secured to the body,'tl1e opposite ends of the fuse elements being secured to the shell, a rod rotatably mounted in the central aperture and. having a portion adapted for contact with the ends of the fuse elements in the notches of the body, yieldable means holding the said end in contact with the respective fuse element in a notch, and means exposed to view through the transparent disc indicating the fuse element contacted by the said rod portion.

6. In a multiple fuse plug, a body of insulating material having a central longitudinal aperture, a series of fuse chambers formed in the surface of the said body circumferentially in spaced relation thereabout, said chambers opening through the surface of the body for a portion of their length adjacent. the inner end and continuing as apertures extending through the head of the lug, a fuse element for each of the chamers having a portion extending upwardly 111 the aperture of 1ts chamber havlng a porby the said shell and shielding the shell to prevent injury thereof by fusing of any fuse element, said elements each having the lower ends project-ing beyondits chamber at the inner end of the body, a ring like member of insulating material adapted to be inserted over the fuse elements 'holding'the said projecting ends of the elements in position andlying between the inner end of the said shell and the said elements, a contact member in the central longitudinal recess having a part thereof-adapted to be positioned to engage the projecting ends of any one of the said fuse elements, and a transparent element sealed to the head of the body closing the fuse chamber apertures therein.

7. In a multiple fuse plug, a body of insulating material having a central longitudinal aperture, a series of fuse chambers formed in the periphery of the body opening through the face thereof, an insulating member covering the openings of the fuse chambers, the central portion of the body extending beyond the inner ends of the fuse chambers, a series of fuse elements one for each of the said chambers and having an end extending over the said projecting end of the body, a threaded shell about the body to the outer end of which the fuse elements are connected, the said insulating material being held in place at the outer end by the shell and sealing the chamber, a ring extending over the inner ends of the fuse elements about the projecting end of the body, said ring supporting the insulating material at the inner ends of the fuse chambers and separating the fuse elements and inner end of the shell, a central contact member adapted to be manually positioned to engage the bent end of any one of the said fuse elements, and a transparent element sealing the outer ends of the fuse chambers, said chambers being vented.

8. In a multiple fuse p-lug,ra body having a central longitudinal aperture, a central contact member extending therethrough, a series of fuse chambers positioned in spaced relation about the periphery of the body opening through each end thereof and through the side of the body fora portion of its length adjacent; the inner end, a threaded metal shell about the said body, a foldable insulating fire resistant member fitting over the inner end of the body and extending about the sides thereof enclosing the open sides of the fuse chambers, a fuse element in each of the chambers, the upper end of which is electrically connected with the shell, said fuse) elements having a bent portion extending toward the outer end of the fuse chamber and provided with a portion of least current carrying capacity near the said end and extending thence to the inner end of the body extending outwardly of the fuse chamber, a ring member of insulating material positioned about the lower end of the body and securing the projecting ends of the fuse elements in position, said member supporting the fire resistant material at the inner ends of the fuse chambers and separating the shell and fuse elements at the said inner end, said central contact member being adapted to be manually positioned to engage any one of the fuse elements, a transparent member sealed to the outer end of the body, and a cap on the outer end of the body each of the fuse chambers having a vent aperture opening beneath the cap.

9. Ina multiple fuse plug, a series of fuse chambers positioned circumferentially thereabout in spaced relation and opening through the eriphery of the body, an insulating mem r providing a cover for the open sides of the chambers, a metal shell about the body supporting the outer end of e the insulating material, a fuse element in each of the chambers connected at the outer end tothe outer end of the shell, and a contact member positioned to engage the inner end of any one of the fuse elements.

10. In a multiple fuse plug, a body of in sulating material having a series of fuse chambers extending in spaced relation about the bod and open through the side thereof adjacent body being enlarged and the chambers extending therethrough, aninsulating member of flexible material adapted to be secured to the inner end of the body and having a series of flaps of a width to cover the open side of each of the chambers sealing the inner open end and open side thereof, a metal the inner end, the upper end of the a shell about the inner end of the body ex- I fuse elements extending through the inner ally positioned to engage any one of the inend of the respective chamber, a ring like ner ends of the fuse elements.

member of insulating material engaging In testimony whereof, We sign this specifi- 10 over said inner ends of the elements holding cation.

the same in position and separating the said a WILLIAM H. TAYLOR.

ends from the inner end of the shell, and a CHAS. W. DOWNS.

central contact member adapted to be manu- JACOB W. BARBEY. 

